Incidental finding of a persistent sciatic artery aneurysm

Abstract

A 78 year old Afro Caribbean male, presented via accident & emergency following a mechanical fall. Work-up investigations revealed an incidental 6.2 cm persistent sciatic artery aneurysm.

Following discussion with the vascular surgeons, lower limb angiography and a lower limb arterial duplex were performed. This demonstrated the true morphology of the persistent sciatic artery where it was shown to be the dominant blood supply to the leg; the superficial femoral artery in comparison was small and petered distally.

Treatment options were considered including embolization of the aneurysm and endovascular repair with a covered stent. Both options were considered too high risk for compromising the blood supply to the entire leg and the patient was managed conservatively.

A persistent sciatic artery (PSA) is a congenital anomaly, with an incidence estimated to be in the region of 0.03%-0.06%. 5 Persistence of the embryological sciatic artery is rare and any patient with a PSA must be managed uniquely and in a considered manner. This case demonstrates the clinical significance of this anatomical variation and the potential pitfalls of treatment without adequate imaging of the lower limb. Patients with a patent sciatic artery are more prone to atherosclerotic degeneration and aneurysm formation, and this occurs in up to 44% ^[1]. Lack of recognition that the main blood supply to the lower leg is from a PSA may lead to inappropriate bypass grafting for what appears otherwise to be an occluded superficial femoral artery.